The invention relates to methods of controlling a vacuum cleaner using various types of sensors. It finds particular application in conjunction with a robotic vacuum having a controller, a cleaning head, and an interconnecting hose assembly and will be described with particular reference thereto. However, it is to be appreciated that the invention is also amenable to other applications. For example, a traditional upright vacuum cleaner, a traditional canister vacuum cleaner, a carpet extractor, other types of vacuum cleaners, and other types of robotic vacuums. More generally, this invention is amenable to various types of robotic household appliances, both indoor, such as floor polishers, and outdoor, such as lawnmowers or window washing robots.
It is well known that robots and robot technology can automate routine household tasks eliminating the need for humans to perform these repetitive and time-consuming tasks. Currently, technology and innovation are both limiting factors in the capability of household cleaning robots. Computer processing power, battery life, electronic sensors such as cameras, and efficient electric motors are all either just becoming available, cost effective, or reliable enough to use in autonomous consumer robots.
Generally, there are two standard types of vacuums: upright and canister. Uprights tend to be more popular because they are smaller, easier to manipulate and less expensive to manufacture. Conversely, the principal advantage of canister vacuums is that, while the canister may be more cumbersome, the cleaning head is smaller. A few patents and published patent applications have disclosed self-propelled and autonomous canister-like vacuum cleaners.
Much of the work on robotic vacuum technology has centered on navigation and obstacle detection and avoidance. The path of a robot determines its success at cleaning an entire floor and dictates whether or not it will get stuck. Some proposed systems have two sets of orthogonal drive wheels to enable the robot to move directly between any two points to increase its maneuverability. Robotic vacuum cleaners have mounted the suction mechanisms on a pivoting or transverse sliding arm so as to increase the reach of the robot. Many robotic vacuums include methods for detecting and avoiding obstacles.
For example, U.S. Pat. No. 6,226,830 to Hendriks et al. and assigned to Philips Electronics discloses a canister-type vacuum cleaner with a self-propelled canister. The vacuum cleaner also includes a conventional cleaning head and a hose assembly connecting the cleaning head to the canister. The canister includes an electric motor, a caster wheel, two drive wheels, a controller, and at least one touch or proximity sensor. The controller controls at least the direction of at least one of the drive wheels. As a user operates the vacuum cleaner and controls the cleaning head, the sensors in the canister detect obstacles and the controller controls the canister to avoid the obstacles.
U.S. Pat. No. 6,370,453 to Sommer discloses an autonomous service robot for automatic suction of dust from floor surfaces. The robot is controlled so as to explore the adjacent area and to detect potential obstacles using special sensors before storing them in a data field. The displacement towards a new location is then carried out using the stored data until the whole accessible surface has been covered. One of the main constituent members of the robot includes an extensible arm that rests on the robot and on which contact and range sensors are arranged. When the robot is used as an automatic vacuum cleaner, airflow is forced into the robot arm. When one or more circular rotary brushes are provided at the front end of the arm, the cleaning effect is enhanced.
U.S. Pat. No. 6,463,368 to Feiten et al. discloses a self-propelled vacuum cleaner. The vacuum cleaner includes a pivotable arm and a cable to connect to an electrical receptacle for power. The arm includes a plurality of tactile sensors to recognize obstacles by touching the obstacle with the arm. The vacuum cleaner also includes a processor and a memory connected via a bus. An identified and traversed path is stored in an electronic map in the memory. Every obstacle identified on the path is entered in the map. The vacuum cleaner includes a cable drum for winding up the cable. The cable drum includes a motor to drive the cable drum for unwinding or winding the cable. The vacuum cleaner also includes a steering mechanism, wheels, and a motor for driving the vacuum cleaner along the path.
PCT Published Patent Application No. WO 02/074150 to Personal Robotics discloses a self-propelled canister vacuum cleaner. In one embodiment, the vacuum cleaner is autonomous. In another embodiment, the self-propelled vacuum cleaner is powered by standard utility power via a power cord. The canister vacuum cleaner includes a cleaning head module, a vacuum fan module (i.e., canister), and a hose assembly connecting the cleaning head module with the vacuum fan module. The vacuum fan module includes a controller that performs navigation and control functions for both the vacuum fan module and the cleaning head module. Alternatively, the controller may be separated from the vacuum fan module and the cleaning head module, and can be mobile. The vacuum fan module and the cleaning head module each include a drive mechanism for propulsion. The cleaning head module includes a cleaning brush assembly that can be motorized or air driven. The cleaning head module may also include a microcontroller that communicates with the controller.
However, none of the current robotic canister-like vacuum cleaners sense suction airflow, floor distance using light wave sensors, floor type using sonic wave sensors, or brush motor current.
U.S. Pat. No. 5,109,566 to Kobayashi et al. discloses a self-running cleaning apparatus with a floor sensor composed of an ultrasonic sensor for sensing the kind of floor surface, such as a carpet or a bare floor, and the state of the floor, such as a concave or convex floor.
U.S. Pat. No. 5,279,672 to Betker et al. discloses an automatic controlled cleaning machine with an infrared drop-off avoidance transmitter and receiver combination.
U.S. Pat. No. 5,321,614 to Ashworth discloses a navigational control apparatus with a plurality of vertical switches connected to a vehicle frame at various points around its periphery. The vertical switches each preferably comprise an electromagnetic switch that contacts the surface of the work area as the vehicle is driven there along and is capable of producing an obstacle signal when surface contact is lost due to a vertical drop greater than a predetermined magnitude. Other sensor means such as opto-electrical proximity sensors may also be employed in place of the electromechanical contact switches.
U.S. Pat. No. 5,341,540 to Soupert et al. discloses an autonomous apparatus for the automatic cleaning of ground areas. At least one sensor may be disposed at the front of the apparatus. This sensor may be of the infrared type and is placed and oriented beneath the apparatus towards the ground area in order to detect a break therein.
U.S. Pat. No. 5,377,106 to Drunk et al. discloses an unmanned vehicle with drop monitoring sensors aimed in a vertical direction detecting increases in the distance between their position and that of the floor traveled on by the vehicle. The drop monitoring sensors are preferably infrared sensors.
U.S. Pat. No. 5,634,237 to Paranjpe discloses a self-guided, self-propelled, convertible cleaning apparatus with a micro controller system that continuously monitors the condition of a suction motor. If the suction motor gets overloaded, the suction motor is stopped and a buzzer is sounded to alert the operator.
U.S. Pat. No. 5,940,927 to Haegermarck et al. discloses an autonomous surface cleaning apparatus. An electronic control device is provided for control of a drive motor associated with a brush roller. If the movement of the brush roller is blocked or obstructed to a predetermined extent, the control device is arranged to stop the brush roller motor and then transitorily activate the motor in the opposite direction and finally, after another stop, to reconnect the brush roller motor to operate in the original direction of rotation.
U.S. Pat. No. 6,493,612 to Bisset et al. discloses an autonomous vehicle, such as a robotic cleaning device, with downward looking wheel sensors that sense the presence of a surface in front of the wheels. Another sensor is provided at or near a leading edge of the vehicle for sensing the presence beneath the leading edge of the vehicle. The vehicle is arranged so that movement of the vehicle is possible if the leading edge sensor senses that there is no surface beneath the leading edge of the vehicle, provided that the wheel sensors indicate that there is a surface adjacent to the wheel. When the leading edge sensor senses that there is no surface beneath the leading edge of the vehicle, the vehicle performs an edge following routine.
U.S. patent application Publication No. US 2002/0189045 to Mori et al. discloses a self-moving cleaner with a level sensor that detects a difference in level of a surface to be cleaned. The level sensor is preferably an infrared sensor and is mounted to each corner of a main body in a manner to face slantingly downward.
U.S. Pat. No. 6,076,227 to Schallig et al. and assigned to Philips discloses an electrical surface treatment device with an acoustic surface type detector. The surface type detector delivers an output signal during operation which is characteristic of the type of surface to be treated and which is determined by a value of a physical quantity of air vibrations reflected by the surface to be treated which value is measured by a vibration detector of the surface type detector. In a special embodiment the physical quantity is an amplitude and the surface type detector is a vibration generator for generating air vibrations having a predetermined amplitude. The generated air vibrations preferably have a frequency of at least 15,000 Hz which varies within a predetermined range.
Thus, there is a particular need for an improved robotic canister-like vacuum cleaner the improvements of which apply to various types of vacuum cleaners, as well as other household appliances, both indoor and outside.